Magnetic couplings of the type being discussed here are counted as belonging to the state of the art and are applied for example with centrifugal pumps, in order to drive-connect the motor shaft to the pump shaft, but also however to mechanically separate these from one another. It is particularly with pumps which are provided for delivering aggressive media that such a magnetic coupling is provided, wherein a can is arranged in the gap between the inner and the outer rotor, and this can forms part of a can pot which hermetically seals the pump to the outside and thus in particular also to the motor.
A magnetic coupling according to the state of the art and in which parallelepiped permanent magnets are located, and are arranged on the one hand in an inner rotor and on the other hand in an outer rotor, is known from EP 2 056 432 A1. The manufacture of such rotors is comparatively cumbersome, since the permanent magnets are to be reliably fixed in the respective rotors. Moreover, the known magnetic coupling has a radial construction height which is caused by the permanent magnets on the one hand, the mechanical construction on the other hand, but also by the necessary soft-magnetic backing serving as a yoke and being necessary, in order to close the magnetic circuits.
The magnetic coupling known from U.S. Pat. No. 6,841,910 B2 and with which the magnets are arranged as a Halbach array, thus have a configuration which renders such a backing superfluous and is magnetically highly effective, is much more favorable inasmuch as this is concerned. The coupling described there however is extremely cumbersome with regard to the construction, since the permanent magnets have a special shape adapted to the respective diameter of the rotors and on the one hand are complex with regard to manufacture and on the other hand are even more complex with regard to assembly.
Moreover, there is also a problem with recycling with the permanent magnets of the couplings of the previously mentioned type. These permanent magnets must be carefully separated from the carrier bodies and only then can be elaborately recycled.